The purified total RNA is suitable for use in a variety of downstream applications, including: RT-PCR, RT-qPCR, Northern blotting, nuclease protection assays, cDNA library preparation after poly (A)+ selection, RNA sequencing, and so on. Serum/plasma samples are first lysed and homogenized in a strong denaturant and phenol containing buffer, which immediately inactivates RNases to ensure isolation of intact RNA. After homogenization, Buffer A is mixed with the lysate and incubated for 3 minutes. And then the mixture is centrifuged for phase separation; the upper-layer supernatant is collected and mixed with ethanol. The liquid is then passed through the RNA binding Spin Column containing a silica-based membrane to which the RNA binds. Impurities are effectively removed by subsequent washing. The purified total RNA is then eluted with Elution Buffer and may be used in a variety of downstream applications.